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1<?xml version='1.0' encoding="UTF-8"?> 1<?xml version='1.0' encoding="UTF-8"?>
2<!-- $Header: /var/cvsroot/gentoo/xml/htdocs/doc/en/alsa-guide.xml,v 1.79 2007/05/07 07:08:24 nightmorph Exp $ -->
3
2<!DOCTYPE guide SYSTEM "/dtd/guide.dtd"> 4<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">
3 5
4<guide link = "/doc/en/alsa-guide.xml"> 6<guide link="/doc/en/alsa-guide.xml">
5<title>Gentoo Linux ALSA Guide</title> 7<title>Gentoo Linux ALSA Guide</title>
6<author title="Author"><mail link="zu@pandora.be"> 8
7 Vincent Verleye</mail> 9<author title="Author">
10 <mail link="fox2mike@gentoo.org">Shyam Mani</mail>
8</author> 11</author>
9<author title="Author"><mail link="g2boojum@gentoo.org"> 12<author title="Author">
10 Grant Goodyear</mail> 13 <mail link="nightmorph@gentoo.org">Joshua Saddler</mail>
11</author> 14</author>
12<author title="Author"><mail link="agenkin@gentoo.org"> 15<author title="Contributor">
13 Arcady Genkin</mail> 16 <mail link="flameeyes@gentoo.org">Diego Pettenò</mail>
14</author> 17</author>
15<author title="Editor"><mail link="zhen@gentoo.org">
16 John P. Davis</mail>
17</author>
18<author title="Editor"><mail link="swift@gentoo.org">
19 Sven Vermeulen</mail>
20</author>
21<author title="Editor"><mail link="bennyc@gentoo.org">
22 Benny Chuang</mail>
23</author>
24<author title="Editor"><mail link="blubber@gentoo.org">
25 Tiemo Kieft</mail>
26</author>
27 18
19<abstract>
20This document helps a user setup ALSA on Gentoo Linux.
21</abstract>
22
23<!-- The content of this document is licensed under the CC-BY-SA license -->
24<!-- See http://creativecommons.org/licenses/by-sa/2.5 -->
28<license/> 25<license/>
29 26
30<abstract>
31This guide will show you how to set up the Advanced Linux Sound Architecture (ALSA) on Gentoo Linux.
32In addition to the Gentoo Linux Desktop Configuration Guide, this guide is supposed to give you more information on this subject. </abstract>
33
34<version>1.3.3</version> 27<version>2.22</version>
35<date>October 9, 2003</date> 28<date>2007-05-07</date>
36 29
37<chapter> 30<chapter>
38<title>Introduction</title> 31<title>Introduction</title>
39<section> 32<section>
40 <title>What is ALSA?</title> 33<title>What is ALSA?</title>
34<body>
35
36<p>
37ALSA, which stands for <e>Advanced Linux Sound Architecture</e>, provides
38audio and MIDI (<e>Musical Instrument Digital Interface</e>) functionality to
39the Linux operating system. ALSA is the default sound subsystem in the 2.6
40kernel thereby replacing OSS (<e>Open Sound System</e>), which was used in the
412.4 kernels.
42</p>
43
44<p>
45ALSA's main features include efficient support for all types of audio
46interfaces ranging from consumer sound cards to professional sound
47equipment, fully modularized drivers, SMP and thread safety, backward
48compatibility with OSS and a user-space library <c>alsa-lib</c> to make
49application development a breeze.
50</p>
51
41<body> 52</body>
42<p> 53</section>
43The Advanced Linux Sound Architecture (ALSA) is a project to improve the Linux sound subsystem by rewriting 54<section>
44large chunks of it. 55<title>ALSA on Gentoo</title>
45It is anticipated that ALSA will make it into Linux kernel 2.6.x (or 3.x.x -- whichever comes first) as it becomes ready. 56<body>
57
46</p> 58<p>
47 59One of Gentoo's main strengths lies in giving the user maximum control over
60how a system is installed/configured. ALSA on Gentoo follows the same
61principle. There are two ways you can get ALSA support up and running on your
62system. We shall look at them in detail in the next chapter.
48<p> 63</p>
49ALSA provides audio and MIDI functionality for Linux. 64
65</body>
66</section>
67</chapter>
68
69<chapter>
70<title>Installing ALSA</title>
71<section>
72<title>Options</title>
73<body>
74
75<warn>
76The methods shown below are mutually exclusive. You cannot have ALSA compiled
77in your kernel and use <c>media-sound/alsa-driver</c>. It <e>will</e> fail.
78</warn>
79
50</p> 80<p>
51 81The two options are:
52<p> 82</p>
53Quoted from <uri>http://www.alsa-project.org</uri>, ALSA has the following features: 83
54<ul><li> Efficient support for all types of audio interfaces, from consumer soundcards to professional multichannel audio interfaces.</li> 84<ol>
55 <li> Fully modularized sound drivers.</li> 85 <li>
56 <li> SMP and thread-safe design.</li> 86 Use ALSA provided by your kernel. This is the preferred/recommended method.
57 <li> User space library (alsa-lib) to simplify application programming and provide higher level functionality.</li> 87 </li>
58 <li> Support for the older OSS API, providing binary compatibility for most OSS programs.</li> 88 <li>Use Gentoo's <c>media-sound/alsa-driver</c> package.</li>
89</ol>
90
91<p>
92The in-kernel drivers and the <c>alsa-driver</c> package can vary a little; it's
93possible that features and fixes found in one might not yet be incorporated into
94the other. The upstream developers are aware of this, but the two drivers are
95effectively separate branches of the ALSA project; they are not entirely
96identical. You should be aware that they might function slightly differently, so
97if one doesn't work for you, try the other! We shall take a peek into both
98before finally deciding on one.
99</p>
100
101<p>
102If you were to use ALSA provided by the kernel, the following are the pros and
103cons:
104</p>
105
106<table>
107<tr>
108 <th>Kernel ALSA</th>
109 <th>Pros and Cons</th>
110</tr>
111<tr>
112 <th>+</th>
113 <ti>
114 No need to emerge yet another package; drivers are integrated into kernel.
115 </ti>
116</tr>
117<tr>
118 <th>+</th>
119 <ti>One shot solution, no repeating emerges.</ti>
120</tr>
121<tr>
122 <th>-</th>
123 <ti>Might be a slightly different version than <c>alsa-driver</c>.</ti>
124</tr>
125</table>
126
127<p>
128And, if you were to use <c>alsa-driver</c>,
129</p>
130
131<table>
132<tr>
133 <th>alsa-driver</th>
134 <th>Pros and Cons</th>
135</tr>
136<tr>
137 <th>+</th>
138 <ti>Possibly the latest drivers from the ALSA Project.</ti>
139</tr>
140<tr>
141 <th>+</th>
142 <ti>Useful if you intend to develop audio drivers.</ti>
143</tr>
144<tr>
145 <th>-</th>
146 <ti>Every kernel recompile requires a re-emerge of <c>alsa-driver</c>.</ti>
147</tr>
148<tr>
149 <th>-</th>
150 <ti>Needs certain kernel config options disabled to work correctly.</ti>
151</tr>
152</table>
153
154</body>
155</section>
156<section>
157<title>So...</title>
158<body>
159
160<p>
161The differences between <c>alsa-driver</c> and the in-kernel ALSA drivers are
162quite subtle, as mentioned earlier. Since there are not any huge differences,
163you are encouraged to go through the process of using the ALSA provided by the
164kernel <e>first</e> for ease of use. Before reporting any sound related issues
165to <uri link="https://bugs.gentoo.org">Gentoo Bugzilla</uri>, please try to
166reproduce them using <c>alsa-driver</c> and file the bug report no matter what
167the result.
168</p>
169
170</body>
171</section>
172<section id="lspci">
173<title>Before you proceed</title>
174<body>
175
176<p>
177Whichever method of install you choose, you need to know what drivers your
178sound card uses. In most cases, sound cards (onboard and otherwise) are PCI
179based and <c>lspci</c> will help you in digging out the required information.
180Please <c>emerge sys-apps/pciutils</c> to get <c>lspci</c>, if you don't have it
181installed already. In case you have a USB sound card, <c>lsusb</c> from
182<c>sys-apps/usbutils</c> <e>might</e> be of help. For ISA cards, try using
183<c>sys-apps/isapnptools</c>. Also, the following pages <e>may</e> help users
184with ISA based sound cards.
185</p>
186
187<ul>
188 <li>
189 <uri link="http://www.roestock.demon.co.uk/isapnptools/">The ISAPNPTOOLS
190 Page</uri>
191 </li>
192 <li>
193 <uri link="http://www2.linuxjournal.com/article/3269">LinuxJournal PnP
194 Article</uri>
195 </li>
196 <li>
197 <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/x320.html">TLDP Sound
198 HowTo</uri>
199 </li>
59</ul> 200</ul>
60There's lots more to ALSA however, like support for Full Duplex playback and recording, multiple soundcard support, 201
61hardware mixing of streams, extensive mixer capabilities (to support advanced features of new soundcards), ... 202<note>
203For ease of use/explanation, we assume the user has a PCI based sound card for
204the remainder of this guide.
205</note>
206
62</p> 207<p>
208We now proceed to find out details about the sound card.
209</p>
210
211<pre caption="Soundcard Details">
212# <i>lspci -v | grep -i audio</i>
2130000:00:0a.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 06)
214</pre>
215
216<p>
217We now know that the sound card on the machine is a Sound Blaster Live! and the
218card manufacturer is Creative Labs. Head over to the <uri
219link="http://bugtrack.alsa-project.org/main/index.php/Matrix:Main">ALSA
220Soundcard Matrix</uri> page and select Creative Labs from the drop down menu.
221You will be taken to the Creative Labs matrix page where you can see that the SB
222Live! uses the <c>emu10k1</c> module. That is the information we need for now.
223If you are interested in detailed information, you can click on the link next to
224the "Details" and that will take you to the <c>emu10k1</c> specific page.
225</p>
226
227<p>
228If you intend to use MIDI, then you should add <c>midi</c> to your USE flags in
229<path>/etc/make.conf</path> before emerging any ALSA packages. Later in the
230guide, we will show you how to set up <uri link="#midi">MIDI support</uri>.
231</p>
232
63</body> 233</body>
64</section>
65<section> 234</section>
66 <title>Why use ALSA?</title> 235<section id="kernel">
67<body> 236<title>Using ALSA provided by your Kernel</title>
68<p>
69If your soundcard is supported by the Linux kernel sound system or the commercial OSS/4Front sound driver system,
70which can be found in all 2.4.x Linux kernels, you could just aswell build <e>those modules</e> for use with your soundcard.
71If you want this, just read through the <uri link="http://www.tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri>.
72</p>
73<p>
74However, those OSS/4Front drivers have some limitations -- being commercial is one.
75ALSA is an attempt to go beyond these limitations and to do so in an open source fashion.
76ALSA is a fully GPL and LGPL'ed sound driver system, that provides a professional quality system for recording, playback,
77and MIDI sequencing.
78</p>
79</body> 237<body>
80</section> 238
239<p>
240If you're a person who likes to keep things simple, then this is the way to go.
241</p>
242
243<note>
244Since the 2005.0 release, Gentoo Linux uses 2.6 as the default kernel. Please
245check that your kernel is a 2.6 series kernel. This method will <e>not</e> work
246on a 2.4 kernel.
247</note>
248
249<p>
250Let us now configure the kernel to enable ALSA.
251</p>
252
253<impo>
254<c>genkernel</c> users should now run <c>genkernel --menuconfig all</c> and
255then follow the instructions in <uri link="#doc_chap2_pre3">Kernel Options for
256ALSA</uri>.
257</impo>
258
259<pre caption="Heading over to the source">
260# <i>cd /usr/src/linux</i>
261# <i>make menuconfig</i>
262</pre>
263
264<note>
265The above example assumes that <path>/usr/src/linux</path> symlink points to
266the kernel sources you want to use. Please ensure the same before proceeding.
267</note>
268
269<p>
270Now we will look at some of the options we will have to enable in the 2.6
271kernel to ensure proper ALSA support for our sound card.
272</p>
273
274<p>
275Please note that for ease of use, all examples show ALSA built as modules. It
276is advisable to follow the same as it then allows the use of <c>alsaconf</c>
277which is a boon when you want to configure your card. Please do <e>not</e> skip
278the <uri link="#alsa-config">Configuration</uri> section of this document. If
279you still like to have options built-in, ensure that you make changes to your
280config accordingly.
281</p>
282
283<pre caption="Kernel Options for ALSA">
284Device Drivers ---&gt;
285 Sound ---&gt;
286
287<comment>(This needs to be enabled)</comment>
288&lt;M&gt; Sound card support
289
290<comment>(Make sure OSS is disabled)</comment>
291Open Sound System ---&gt;
292 &lt; &gt; Open Sound System (DEPRECATED)
293
294<comment>(Move one step back and enter ALSA)</comment>
295Advanced Linux Sound Architecture ---&gt;
296 &lt;M&gt; Advanced Linux Sound Architecture
297 <comment>(Select this if you want MIDI sequencing and routing)</comment>
298 &lt;M&gt; Sequencer support
299 <comment>(Old style /dev/mixer* and /dev/dsp* support. Recommended.)</comment>
300 &lt;M&gt; OSS Mixer API
301 &lt;M&gt; OSS PCM (digital audio) API
302
303<comment>(You now have a choice of devices to enable support for. Generally,
304you will have one type of device and not more. If you have more than one
305sound card, please enable them all here.)</comment>
306
307<comment>(Mostly for testing and development purposes, not needed for normal
308users unless you know what you are doing.)</comment>
309Generic devices ---&gt;
310
311<comment>(For ISA Sound cards)</comment>
312ISA devices ---&gt;
313<comment>(IF you had the Gravis, you would select this option)</comment>
314 &lt;M&gt; Gravis UltraSound Extreme
315
316<comment>(Move one level back and into PCI devices. Most sound cards today are
317PCI devices)</comment>
318PCI devices ---&gt;
319 <comment>(We now select the emu10k1 driver for our card)</comment>
320 &lt;M&gt; Emu10k1 (SB Live!, Audigy, E-mu APS)
321 <comment>(Or an Intel card would be)</comment>
322 &lt;M&gt; Intel/SiS/nVidia/AMD/ALi AC97 Controller
323 <comment>(Or if you have a VIA Card)</comment>
324 &lt;M&gt; VIA 82C686A/B, 8233/8235 AC97 Controller
325
326<comment>(Move one level back and select in case you have an USB sound card)</comment>
327USB Devices ---&gt;
328</pre>
329
330<p>
331Now that your options are set, you can (re)compile the kernel and ALSA support
332for your card should be functional once you reboot into the new kernel. Don't
333forget to update your GRUB configuration to use the newly built kernel.
334You can now proceed to <uri link="#alsa-utilities">ALSA Utilities</uri> and
335see if everything is working as it should.
336</p>
337
338</body>
81<section> 339</section>
82 <title>What cards does ALSA support?</title> 340<section id="alsa-driver">
341<title>Using the ALSA Driver package</title>
83<body> 342<body>
84<p> 343
85ALSA tries to support as many (new) cards as possible by providing open-source drivers.
86However, some vendors may provide binary-only packages.
87</p> 344<p>
88<p>To know if your card is supported, you can find a Soundcard Matrix of supported and not-supported cards here: 345So you've decided to go the <c>alsa-driver</c> way. Let's get started then.
89<uri>http://www.alsa-project.org/alsa-doc/</uri>. 346There are a few minor things to be done to ensure only the drivers for your
347sound card are compiled. Although this is not really necessary, it cuts down
348on the unnecessary drivers that will be compiled otherwise.
349</p>
350
90</p> 351<p>
352If you don't have an idea of what drivers your sound card might need, please
353take a look at the <uri link="#lspci">lspci</uri> section of this guide. Once
354you have your driver name (<c>emu10k1</c> in our example), edit
355<path>/etc/make.conf</path> and add a variable, <c>ALSA_CARDS</c>.
356</p>
357
358<pre caption="Adding ALSA_CARDS to make.conf">
359<comment>(For one sound card)</comment>
360ALSA_CARDS="emu10k1"
361<comment>(For more than one, separate names with spaces)</comment>
362ALSA_CARDS="emu10k1 via82xx"
363</pre>
364
365<p>
366If you have compiled your kernel and want to use <c>alsa-driver</c>, please
367ensure the following before proceeding, else <c>alsa-driver</c> is likely to
368fail. The next code listing gives you one way of performing the checks.
369</p>
370
371<note>
372<c>genkernel</c> users can proceed with <uri link="#doc_chap2_pre6">Installing
373alsa-driver</uri> as their configuration is in sync with the one shown below by
374default.
375</note>
376
377<ol>
378 <li>
379 <c>CONFIG_SOUND</c> is set. (Basic Sound support enabled)
380 </li>
381 <li>
382 <c>CONFIG_SOUND_PRIME</c> is not set. (In-built OSS support disabled)
383 </li>
384 <li>
385 <c>CONFIG_SND</c> is not set. (In-built ALSA support disabled)
386 </li>
387 <li>
388 <path>/usr/src/linux</path> points to the kernel you want ALSA working on.
389 </li>
390</ol>
391
392<pre caption=".config checks">
393<comment>(Assuming the linux symlink points to the correct kernel)</comment>
394# <i>cd /usr/src/linux</i>
395# <i>grep SOUND .config</i>
396<comment>(1. is true)</comment>
397CONFIG_SOUND=y
398<comment>(2. is true)</comment>
399CONFIG_SOUND_PRIME is not set
400# <i>grep SND .config</i>
401<comment>(and 3. is true)</comment>
402CONFIG_SND is not set
403</pre>
404
405<p>
406Now all you have to do is type the magic words... and no, it's not abracadabra.
407</p>
408
409<pre caption="Installing alsa-driver">
410# <i>emerge alsa-driver</i>
411</pre>
412
413<impo>
414Please note that you will have to run <c>emerge alsa-driver</c> after every
415kernel (re)compile, as the earlier drivers are deleted. To make this task
416easier, you may want to emerge the <c>module-rebuild</c> package, which will
417keep track of module packages and rebuild them for you. First run
418<c>module-rebuild populate</c> to create the list, and then after every kernel
419(re)compile, you just run <c>module-rebuild rebuild</c>, and your external
420modules will be rebuilt.
421</impo>
422
91</body> 423</body>
92</section> 424</section>
93</chapter> 425</chapter>
94 426
95<chapter> 427<chapter>
96<title>Installation</title> 428<title>Configuring/Testing ALSA</title>
97<section> 429<section id="alsa-utilities">
98<title>Gentoo USE flags</title> 430<title>ALSA Utilities</title>
99<body>
100
101<p>
102To compile programs with ALSA-support, be sure to add <e>alsa</e> to
103your USE-variable. However, several tools don't support alsa yet, and
104require OSS. ALSA provides OSS-emulation if you define <e>oss</e> in your
105USE-variable before you start.
106</p>
107
108</body> 431<body>
109</section>
110 432
111<section>
112 <title>Kernel modules</title>
113<body>
114<p>
115Since we're still using 2.4.x kernel sources, we'll have to compile kernel modules and ALSA modules separately. People who are using a 2.5.x kernel can do this from within their kernel configuration, since the ALSA modules are included in the kernel sources and should be built there.
116</p> 433<p>
434<c>alsa-utils</c> forms an integral part of ALSA as it has a truckload of
435programs that are highly useful, including the ALSA Initscripts. Hence we
436strongly recommend that you install <c>alsa-utils</c>
117<p> 437</p>
118First we'll make sure that our kernel configuration is ready for use with ALSA. 438
119All you need in your kernel configuration is having Sound Card Support set to be built as a module (M). 439<pre caption="Install alsa-utils">
120This will build <c>soundcore.o</c>. 440# <i>emerge alsa-utils</i>
121</p> 441</pre>
122<p> 442
123<note> 443<note>
124Possibly, this will also work when you built Sound Card Support in the kernel (Y) instead of building it as a module (M). 444If you activated ALSA in your <uri link="#kernel">kernel</uri> <e>and</e> did
125However, the official ALSA documentation suggests building it as a module, since ALSA will try loading it. 445not compile ALSA as modules, please proceed to the
446<uri link="#initscript">ALSA Initscript</uri> section. The rest of you need
447to configure ALSA. This is made very easy by the existence of the
448<c>alsaconf</c> tool provided by <c>alsa-utils</c>.
126</note> 449</note>
450
451</body>
452</section>
453<section id="alsa-config">
454<title>Configuration</title>
455<body>
456
127</p> 457<p>
128<p>If you already have a working kernel configuration, make sure you remove all sound drivers (except for Sound Card Support). 458Recent versions of <c>udev</c> (<c>>=udev-103</c>) provide some degree of
129If you wish to do this without having to reboot, you could do like this: 459kernel-level autoconfiguration of your sound card. If possible, try to rely on
460just letting your kernel automatically setup your sound card for you. Otherwise,
461use <c>alsaconf</c> to configure your card, as shown below.
462</p>
463
464<note>
465Please shut down any programs that <e>might</e> access the sound card while
466running <c>alsaconf</c>.
467</note>
468
130</p> 469<p>
470Another way to configure your sound card is to run <c>alsaconf</c>. Just type
471<c>alsaconf</c> in a shell as root.
472</p>
473
474<pre caption="Invoking alsaconf">
475# <i>alsaconf</i>
131<pre> 476</pre>
132# <i>cd /usr/src/linux</i> 477
133# <i>cp .config ~/</i>
134# <i>make mrproper</i>
135# <i>cp ~/.config .</i>
136# <i>make menuconfig</i>
137</pre>
138<p>
139Now select <e>Sound Card Support</e> as Module (M) and deselect all other sound drivers.
140Exit and say Y to save your kernel configuration.
141After that, build the modules:
142</p> 478<p>
479You will now see a neat menu guided interface that will automatically probe
480your devices and try to find out your sound card. You will be asked to pick
481your sound card from a list. Once that's done, it will ask you permission to
482automatically make required changes to <path>/etc/modules.d/alsa</path>.
483It will then adjust your volume settings to optimum levels, run
484<c>update-modules</c> and start the <path>/etc/init.d/alsasound</path> service.
485Once <c>alsaconf</c> exits, you can proceed with setting up the ALSA
486initscript.
487</p>
488
489</body>
490</section>
491<section id="initscript">
492<title>ALSA Initscript</title>
493<body>
494
495<p>
496We're now almost all setup. Whichever method you chose to install ALSA, you'll
497need to have something load your modules or initialize ALSA and restore your
498volume settings when your system comes up. The ALSA Initscript handles all of
499this for you and is called <c>alsasound</c>. Add it to the boot runlevel.
500</p>
501
502<pre caption="Adding ALSA to the boot runlevel">
503# <i>rc-update add alsasound boot</i>
504 * alsasound added to runlevel boot
505 * rc-update complete.
143<pre> 506</pre>
144# <i>make dep clean</i> 507
145# <i>make modules modules_install</i>
146</pre>
147<p>
148Before installing your new modules, this last line will delete all your previous modules,
149even the ones from a previous ALSA installation.
150</p> 508<p>
509Next, just check the <path>/etc/conf.d/alsasound</path> file and ensure that
510SAVE_ON_STOP variable is set to yes. This saves your sound settings when you
511shutdown your system.
151<p> 512</p>
513
514</body>
515</section>
516<section>
517<title>Audio Group</title>
518<body>
519
520<p>
521Before we move on to testing, there's one last <e>important</e> thing that needs
522to be setup. Rule of thumb in a *nix OS: Do not run as root unless needed.
523This applies here as well ;) How? Well, most of the times you should be logged
524in as a user and would like to listen to music or access your soundcard. For
525that to happen, you need to be in the "audio" group. At this point, we'll add
526users to the audio group, so that they won't have any issues when they want to
527access sound devices. We'll use <c>gpasswd</c> here and you need to be logged in
528as root for this to work.
529</p>
530
531<pre caption="Adding users to the audio group">
532<comment>(Substitute &lt;username&gt; with your user)</comment>
533# <i>gpasswd -a &lt;username&gt; audio </i>
534Adding user &lt;username&gt; to group audio
535</pre>
536
537</body>
538</section>
539<section>
540<title>Volume Check!</title>
541<body>
542
543<p>
544We've completed all the setups and prerequisites, so let's fire up ALSA. If
545you ran <c>alsaconf</c>, you can skip this step, since <c>alsaconf</c> already
546does this for you.
547</p>
548
549<pre caption="Start the service">
550# <i>/etc/init.d/alsasound start</i>
551</pre>
552
553<p>
554Now that the required things have been taken care of, we need to check up on
555the volume as in certain cases, it is muted. We use <c>alsamixer</c> for this
556purpose.
557</p>
558
559<pre caption="Starting alsamixer">
560<comment>(Opens up a console program. Only required settings are shown)</comment>
561# <i>alsamixer</i>
562</pre>
563
152<impo> 564<impo>
153This means, whenever you recompile your kernel later on, you MUST recompile <c>alsa-driver</c>. 565If you have issues starting up <c>alsamixer</c> and get errors such as
566alsamixer: function snd_ctl_open failed for default: No such file or directory,
567this is usually an issue with udev setting up the devices. Run <c>killall
568udevd; udevstart</c> to reload <path>/dev</path> entries and fire up
569<c>alsamixer</c>. It should solve the issue.
154</impo> 570</impo>
571
155</p> 572<p>
573This is how the ALSA Mixer <e>might</e> look the first time you open it. Pay
574attention to the Master and PCM channels which both have an MM below them.
575That means they are muted. If you try to play anything with <c>alsamixer</c>
576in this state, you will not hear anything on your speakers.
156<p> 577</p>
157<note>However, there's no need to reinstall <c>nvidia-kernel</c>, the Nvidia drivers are in a separate directory 578
158in <path>/lib/modules/*/video</path> and won't get deleted by a <c>make modules modules_install</c> 579<figure link="/images/docs/alsa-mixermuted.png" short="AlsaMixer Muted" caption="The Alsa Mixer Main Window, Muted"/>
580
581<p>
582Now, we shall unmute the channels, and set volume levels as needed.
583</p>
584
585<warn>
586Both Master <e>and</e> PCM need to be unmuted and set to audible volume levels
587if you want to hear some output on your speakers.
588</warn>
589
590<ul>
591 <li>
592 To move between channels, use your left and right arrow keys. (&lt;-
593 &amp; -&gt;)
594 </li>
595 <li>
596 To toggle mute, move to the specific channel, for example Master and press
597 the <e>m</e> key on the keyboard.
598 </li>
599 <li>
600 To increase and decrease the volume levels, use the up and down arrow keys
601 respectively.
602 </li>
603</ul>
604
605<note>
606Be careful when setting your Bass and Treble values. 50 is usually a good
607number for both. Extremely high values of Bass may cause <e>jarring</e>
608on speakers that are not designed to handle them.
159</note> 609</note>
610
160</p> 611<p>
161</body> 612After you're all done, your ALSA Mixer should look similar to the one below.
162</section> 613Note the 00 instead of the MM and also the volume levels for some optimum
614settings.
615</p>
163 616
617<figure link="/images/docs/alsa-mixerunmuted.png" short="AlsaMixer Unmuted" caption="Alsa Mixer ready to roll"/>
618
619</body>
164<section> 620</section>
165 <title>ALSA modules</title> 621<section>
622<title>Sound Check!</title>
623<body>
624
625<p>
626Finally. Some music. If everything above is perfect, you should now be able to
627listen to some good music. A quick way to test is to use a command line tool
628like <c>media-sound/madplay</c>. You could also use something more well known
629like <c>mpg123</c>. If you are an ogg fan, you could use <c>ogg123</c> provided
630by <c>media-sound/vorbis-tools</c>. Use any player you are comfortable with. As
631always, <c>emerge</c> what you need.
632</p>
633
634<pre caption="Getting the software">
635<comment>(Install the applications you want)</comment>
636# <i>emerge madplay mpg123</i>
637<comment>(To play .ogg files)</comment>
638# <i>emerge vorbis-tools</i>
639</pre>
640
641<p>
642And then play your favorite sound track...
643</p>
644
645<pre caption="Playing Music">
646# <i>madplay -v /mnt/shyam/Music/Paul\ Oakenfold\ -\ Dread\ Rock.mp3</i>
647MPEG Audio Decoder 0.15.2 (beta) - Copyright (C) 2000-2004 Robert Leslie et al.
648 Title: Dread Rock
649 Artist: Paul Oakenfold
650 Album: Matrix Reloaded
651 Year: 2003
652 Genre: Soundtrack
653 Soundtrack
654 00:04:19 Layer III, 160 kbps, 44100 Hz, joint stereo (MS), no CRC
655
656# <i>ogg123 Paul\ Oakenfold\ -\ Dread\ Rock.ogg</i>
657Audio Device: Advanced Linux Sound Architecture (ALSA) output
658
659Playing: Paul Oakenfold - Dread Rock.ogg
660Ogg Vorbis stream: 2 channel, 44100 Hz
661Genre: Soundtrack
662Transcoded: mp3;160
663Title: Dread Rock
664Artist: Paul Oakenfold
665Date: 2003
666Album: Matrix Reloaded
667Time: 00:11.31 [04:28.75] of 04:40.06 (200.6 kbps) Output Buffer 96.9%
668</pre>
669
166<body> 670</body>
671</section>
672<section>
673<title>ALSA and USE</title>
674<body>
167 675
168<p>
169Now it's time to install the ALSA drivers for your soundcard(s). If your soundcard is PCI, you can find out the name
170and type of your soundcard by looking at the output of /proc/pci.
171</p> 676<p>
677You can now add the <c>alsa</c> use flag to <path>/etc/make.conf</path> to
678ensure that your applications that support ALSA get built with it. Some
679architectures like x86 and amd64 have the flag enabled by default.
680</p>
681
682</body>
683</section>
684<section>
685<title>Issues?</title>
686<body>
687
688<p>
689If for some reason you're unable to hear sound, the first thing to do would
690be to check your <uri link="#doc_chap3_pre6">alsamixer</uri> settings. 80% of
691the issues lie with muted channels or low volume. Also check your Window
692Manager's sound applet and verify that volumes are set to audible levels.
693</p>
694
695<p>
696<path>/proc</path> is your friend. And in this case, <path>/proc/asound</path>
697is your best friend. We shall just take a short look at how much info is made
698available to us there.
699</p>
700
701<pre caption="Fun with /proc/asound">
702<comment>(First and foremost, if /proc/asound/cards shows your card, ALSA has
703picked up your sound card fine.)</comment>
704# <i>cat /proc/asound/cards</i>
7050 [Live ]: EMU10K1 - Sound Blaster Live!
706 Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
707
708<comment>(This displays the current running ALSA version)</comment>
709# <i>cat /proc/asound/version</i>
710Advanced Linux Sound Architecture Driver Version 1.0.8 (Thu Jan 13 09:39:32 2005 UTC).
711
712<comment>(ALSA OSS emulation details)</comment>
713# <i>cat /proc/asound/oss/sndstat</i>
714Sound Driver:3.8.1a-980706 (ALSA v1.0.8 emulation code)
715Kernel: Linux airwolf.zion 2.6.11ac1 #2 Wed May 4 00:35:08 IST 2005 i686
716Config options: 0
717
718Installed drivers:
719Type 10: ALSA emulation
720
721Card config:
722Sound Blaster Live! (rev.6, serial:0x80271102) at 0xb800, irq 11
723
724Audio devices:
7250: EMU10K1 (DUPLEX)
726
727Synth devices: NOT ENABLED IN CONFIG
728
729Midi devices:
7300: EMU10K1 MPU-401 (UART)
731
732Timers:
7337: system timer
734
735Mixers:
7360: SigmaTel STAC9721/23
172<pre> 737</pre>
173# <i>grep audio /proc/pci</i>
174</pre>
175 738
176
177<p>
178<warn>
179If you had a previous sound setup and there are still non-ALSA sound modules loaded, unload them <e>now</e>.
180Check with <c>lsmod</c> and use <c>rmmod</c> to unload all sound-related modules on your system.
181</warn>
182</p> 739<p>
183 740The other most common issue users face is the dreaded "Unknown symbol in module"
741error. An example of the same is shown below.
184<p> 742</p>
185We could simply do an <c>emerge alsa-driver</c> now, this would compile and install <e>all</e> ALSA sound drivers.
186</p>
187<p>
188However, to save some time, lookup the <e>Module Name</e> of your soundcard(s) on the
189<uri link="http://www.alsa-project.org/alsa-doc">ALSA Soundcard Matrix</uri> by following the <e>Details</e> link in the <e>Driver and Docs</e> column in the row of the chipset of your soundcard.
190Mine is <c>snd-emu10k1</c>, since I have an SBlive! soundcard, with the <e>EMU10K1</e> chipset.
191We'll set ALSA_CARDS environment to the value of the module name before emerging (but without the snd prefix), so emerge will only compile the drivers we need.
192</p>
193 743
744<pre caption="Unknown Symbol in module error">
745# <i>/etc/init.d/alsasound start</i>
746 * Loading ALSA modules ...
747 * Loading: snd-card-0 ... [ ok ]
748 * Loading: snd-pcm-oss ...
749WARNING: Error inserting snd_mixer_oss
750(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
751symbol in module, or unknown parameter (see dmesg) FATAL: Error inserting
752snd_pcm_oss
753(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-pcm-oss.ko): Unknown
754symbol in module, or unknown parameter (see dmesg)
755 [ !! ]
756 * Loading: snd-mixer-oss ...
757FATAL: Error inserting snd_mixer_oss
758(/lib/modules/2.6.12-gentoo-r6/kernel/sound/core/oss/snd-mixer-oss.ko): Unknown
759symbol in module, or unknown parameter (see dmesg)
760 [ !! ]
761 * Loading: snd-seq ... [ ok ]
762 * Loading: snd-emu10k1-synth ... [ ok ]
763 * Loading: snd-seq-midi ... [ ok ]
764 * Restoring Mixer Levels ... [ ok ]
194<pre> 765</pre>
195# <i>env ALSA_CARDS='emu10k1' emerge alsa-driver</i> 766
767<p>
768And when you take a look at <c>dmesg</c> as suggested, you're quite likely to
769see:
196</pre> 770</p>
771
772<pre caption="dmesg output">
773<comment>(Only relevant portions are shown below)</comment>
774# <i>dmesg | less</i>
775ACPI: PCI Interrupt 0000:02:06.0[A] -> Link [APC3] -> GSI 18 (level, low) -> IRQ 209
776snd_mixer_oss: Unknown symbol snd_unregister_oss_device
777snd_mixer_oss: Unknown symbol snd_register_oss_device
778snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
779snd_mixer_oss: Unknown symbol snd_oss_info_register
780snd_pcm_oss: Unknown symbol snd_unregister_oss_device
781snd_pcm_oss: Unknown symbol snd_register_oss_device
782snd_pcm_oss: Unknown symbol snd_mixer_oss_ioctl_card
783snd_pcm_oss: Unknown symbol snd_oss_info_register
784snd_mixer_oss: Unknown symbol snd_unregister_oss_device
785snd_mixer_oss: Unknown symbol snd_register_oss_device
786snd_mixer_oss: Unknown symbol snd_mixer_oss_notify_callback
787snd_mixer_oss: Unknown symbol snd_oss_info_register
788</pre>
789
790<p>
791The above issue is caused when you switch from <c>alsa-driver</c> to in-kernel
792ALSA because when you unmerge <c>alsa-driver</c> the module files are config
793protected and hence get left behind. So, when you switch to in-kernel
794drivers, running <c>modprobe</c> gives you a mix of <c>alsa-driver</c> and
795in-kernel modules thus causing the above errors.
796</p>
797
798<p>
799The solution is quite easy. We just need to manually remove the problem causing
800directory after you unmerge <c>alsa-driver</c>. Be sure to remove the correct
801kernel version and not the current one!
802</p>
803
804<pre caption="Removing the alsa-driver modules">
805# <i>rm -rf /lib/modules/$(uname -r)/alsa-driver</i>
806</pre>
807
808<p>
809Another reason for error messages similar to the ones above could be a file in
810<path>/etc/modules.d</path> supplying a <c>device_mode</c> parameter when it
811isn't required. Confirm that this is indeed the issue and find out which file
812is the culprit.
813</p>
814
815<pre caption="Confirming and searching for device_mode">
816<comment>(Check dmesg to confirm)</comment>
817# <i>dmesg | grep device_mode</i>
818snd: Unknown parameter `device_mode'
819<comment>(Now, to get to the source of the issue)</comment>
820# <i>grep device_mode /etc/modules.d/*</i>
821</pre>
822
823<p>
824Usually it is a file called <path>alsa</path> with the line <c>options snd
825device_mode=0666</c>. Remove this line and restart the alsasound service and
826that should take care of this issue.
827</p>
828
829</body>
830</section>
831</chapter>
832
833<chapter>
834<title>Other things ALSA</title>
835<section id="midi">
836<title>Setting up MIDI support</title>
837<body>
838
839<p>
840First, check to make sure that you enabled the <c>midi</c> USE flag in
841<path>/etc/make.conf</path>. If you didn't, go ahead and add it now. You will
842also need to re-emerge any ALSA packages that use the <c>midi</c> flag, such as
843<c>alsa-lib</c>, <c>alsa-utils</c>, and <c>alsa-driver</c>.
844</p>
845
846<p>
847If your sound card is one of those that come with on-board MIDI synthesizers
848and you would like to listen to some .mid files, you have to install
849<c>awesfx</c> which is basically a set of utilities for controlling the AWE32
850driver. We need to install it first. If you don't have a hardware synthesizer,
851you can use a virtual one. Please see the section on
852<uri link="#vsynth">Virtual Synthesizers</uri> for more information.
853</p>
854
855<pre caption="Installing awesfx">
856# <i>emerge awesfx</i>
857</pre>
858
197<note> 859<note>
198You can also add this value in <path>/etc/make.conf</path>, so when you have to emerge the alsa-driver later on you can just run <c>emerge alsa-driver</c>. 860You will need to copy over SoundFont (SF2) files from your sound card's driver
199For example, like this: <c>echo 'ALSA_CARDS="emu10k1"' >> /etc/make.conf</c> 861CD or a Windows installation into <path>/usr/share/sounds/sf2/</path>. For
862example a sound font file for the Creative SBLive! card would be 8MBGMSFX.SF2.
200</note> 863</note>
201 864
865<p>
866After copying over the Soundfont files, we can then play a midi file as shown.
867You can also add the <c>asfxload</c> command to
868<path>/etc/conf.d/local.start</path>, so that the sound font is loaded
869every time the system starts up.
870</p>
871
202<note> 872<note>
203When you want to install ALSA drivers for more than one soundcard, you could set ALSA_CARDS to a space-separated list 873<path>/mnt</path> paths mentioned in the code listing(s) below will <e>not</e>
204of drivers; like this: <c>env ALSA_CARDS='emu10k1 intel8x0 ens1370' emerge alsa-driver</c> 874be the same in your machine. They are just an example. Please be careful to
875change the path to suit your machine.
205</note> 876</note>
206 877
207<note>If you want to have OSS compatibility, make sure to emerge <i>alsa-oss</i>, it is the ALSA/OSS compatibility 878<pre caption="Loading Soundfonts">
208wrapper. </note> 879<comment>(First, copy the Soundfont)</comment>
880# <i>cp /mnt/win2k/Program\ Files/CreativeSBLive2k/SFBank/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
881<comment>(Or get it from your SoundBlaster CD)</comment>
882# <i>cp /mnt/cdrom/AUDIO/ENGLISH/SFBANK/8MBGMSFX.SF2 /usr/share/sounds/sf2/</i>
883<comment>(We load the specific Soundfont)</comment>
884# <i>asfxload /usr/share/sounds/sf2/8MBGMSFX.SF2</i>
885</pre>
209 886
210<note>If you plan on recompiling your kernels numerous times, it might
211be adviseable to emerge <c>alsa-driver</c> with <c>--buildpkg</c>. This
212will create a binary package for it. Later, after recompiling your kernel,
213you can just do <c>emerge --usepkg alsa-driver</c> which will install the
214binary package instead of recompiling it completely.</note>
215
216<p>
217After this, the ALSA modules should be installed on your system.
218</p> 887<p>
888You can now play midi files using a program like <c>aplaymidi</c>. Run
889<c>aplaymidi -l</c> to get a list of available ports and then pick one
890to play the file on.
891</p>
892
893<pre caption="Playing MIDI">
894<comment>(Check open ports)</comment>
895# <i>aplaymidi -l</i>
896 Port Client name Port name
897 64:0 EMU10K1 MPU-401 (UART) EMU10K1 MPU-401 (UART)
898 65:0 Emu10k1 WaveTable Emu10k1 Port 0
899 65:1 Emu10k1 WaveTable Emu10k1 Port 1
900 65:2 Emu10k1 WaveTable Emu10k1 Port 2
901 65:3 Emu10k1 WaveTable Emu10k1 Port 3
902<comment>(Pick a port, and play a mid file)</comment>
903# <i> aplaymidi --port=65:0 /mnt/shyam/music/midi/mi2.mid</i>
904</pre>
905
219</body> 906</body>
220</section>
221<section> 907</section>
222 <title>Configuration of ALSA</title> 908<section id="vsynth">
223<body> 909<title>Virtual Synthesizers</title>
224<p>
225Let's start configuring now to get ALSA working properly.
226We'll need to edit some files, to let our system know about the freshly installed ALSA modules.
227</p>
228
229<p>
230First, install <c>alsa-utils</c> on your system:
231</p>
232
233<pre caption = "Emerging alsa-utils">
234# <i>emerge alsa-utils</i>
235</pre>
236
237<p>
238Hereafter, we need to edit <path>/etc/modules.d/alsa</path>.
239</p>
240<warn>
241There is no need to edit <path>/etc/modules.conf</path>. Instead, always edit files in <path>/etc/modules.d</path>.
242</warn>
243<p>
244Check the ALSA portion <e>at the bottom of the file</e>.
245By tweaking this line you can specify the max number of soundcards you have (generally, just one).
246</p>
247<pre caption="At the bottom of /etc/modules.d/alsa">
248<comment>Set this to the correct number of cards.</comment>
249options snd cards_limit=1
250</pre>
251<p>
252Now we'll specify the sounddriver(s) ALSA should use. In the same file, edit like this:
253</p>
254<pre caption="In /etc/modules.d/alsa">
255## and then run `modules-update' command.
256## Read alsa-driver's INSTALL file in /usr/share/doc for more info.
257##
258## ALSA portion
259alias snd-card-0 snd-emu10k1
260<comment>## If you have more than one, add:</comment>
261## alias snd-card-1 snd-intel8x0
262## alias snd-card-2 snd-ens1370
263## OSS/Free portion
264## alias sound-slot-0 snd-card-0
265## alias sound-slot-1 snd-card-1
266##
267</pre>
268<note>
269If you have more than one soundcard, adjust the <c>cards_limit</c> value and add more snd-card aliases to the file.
270I don't have experience with this, but you can find examples for configurations with two or more soundcards in
271<uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/c1660.htm">Chapter 6</uri>
272of the <uri link="http://www.alsa-project.org/alsa-doc/alsa-howto/alsa-howto.html">ALSA Howto</uri>.
273</note>
274<p>
275Last thing to do in this file, almost at the end, check if these lines are there and uncommented:
276</p>
277<pre caption="Near the end of /etc/modules.d/alsa">
278alias /dev/mixer snd-mixer-oss
279alias /dev/dsp snd-pcm-oss
280alias /dev/midi snd-seq-oss
281</pre>
282<p>
283Now double-check the file <path>/etc/modules.d/alsa</path> and when you're sure everyting is ok, run <c>modules-update</c>.
284<pre>
285# <i>modules-update</i>
286</pre>
287</p>
288<note>
289Running <c>modules-update</c> here will insert the data from <path>/etc/modules.d/alsa</path> into <path>/etc/modules.conf</path>
290</note>
291<p>
292You should also verify that /etc/devfsd.conf has the alsa devices and permissions correctly registered.
293</p>
294<pre caption="/etc/devfsd.conf">
295# ALSA/OSS stuff
296# Comment/change these if you want to change the permissions on
297# the audio devices
298LOOKUP snd MODLOAD ACTION snd
299LOOKUP dsp MODLOAD
300LOOKUP mixer MODLOAD
301LOOKUP midi MODLOAD
302REGISTER sound/.* PERMISSIONS root.audio 660
303REGISTER snd/.* PERMISSIONS root.audio 660
304</pre>
305<note>
306Notice that devfsd.conf sets /dev/sound permissions to be root.audio. Thus, for non-root users to use audio they will have to be part of the audio group.
307</note>
308</body> 910<body>
309</section> 911
310</chapter> 912<p>
311<chapter> 913If your sound card lacks a hardware synthesizer, you could use a virtual one
312<title>Starting ALSA</title> 914like <c>timidity++</c>. Installation is a breeze.
915</p>
916
917<pre caption="Installing timidity++">
918# <i>emerge timidity++</i>
919</pre>
920
921<p>
922For timidity to play sounds, it needs a sound font. Fortunately, the ebuild will
923install some sound font packages for you. There are a few other font packages
924available in Portage, such as <c>timidity-freepats</c> and
925<c>timidity-eawpatches</c>. You can have multiple sound font configurations
926installed, and you can place your own in <path>/usr/share/timidity/</path>. To
927switch between different timidity configurations, you should use
928<c>eselect</c>.
929</p>
930
931<pre caption="Changing configurations">
932# <i>eselect timidity list</i>
933# <i>eselect timidity set eawpatches</i>
934</pre>
935
936<p>
937Don't forget to add <c>timidity</c> to the default runlevel.
938</p>
939
940<pre caption="Adding timidity to the default runlevel">
941# <i>rc-update add timidity default</i>
942# <i>/etc/init.d/timidity start</i>
943</pre>
944
945<p>
946You can now try out <uri link="#doc_chap4_pre3">Playing MIDI</uri> files.
947</p>
948
949</body>
313<section> 950</section>
314 <title>Adding alsasound to a runlevel</title>
315<body>
316<p>
317First thing to do now, is to make ALSA startup at boottime. Like this:
318<pre>
319# <i>rc-update add alsasound boot</i>
320</pre>
321</p>
322<p>
323<warn>Note that the alsasound script should be added to the "boot" runlevel, not the "default" runlevel.</warn>
324</p>
325</body>
326</section> 951<section>
952<title>Tools and Firmware</title>
953<body>
954
955<p>
956Some specific sound cards can benefit from certain tools provided by the
957<c>alsa-tools</c> and <c>alsa-firmware</c> packages. You may install either with
958a simple <c>emerge</c>.
959</p>
960
961<pre caption="Installing ALSA Tools">
962# <i>emerge alsa-tools</i>
963</pre>
964
965</body>
327<section> 966</section>
328 <title>Running and unmuting</title>
329<body>
330<p>
331Since we're Linux users, we don't want to reboot. So we'll start the alsasound script manually.
332</p>
333<pre>
334# <i>/etc/init.d/alsasound start</i>
335</pre>
336<p>
337ALSA is running now. If everything is ok, you should be able to see the ALSA modules loaded when running <c>lsmod</c>.
338However, sound won't work yet, because the channels are still muted. We need <c>amixer</c> for this.
339</p>
340<pre caption = "Running amixer">
341# <i>amixer</i>
342</pre>
343<p>
344<warn>
345You shouldn't get this, but <e>if</e> you get an error about "amixer: Mixer attach default error: No such file or directory", you should manually modprobe
346<c>snd-mixer-oss</c> and <c>snd-pcm-oss</c> once. After that run amixer again.
347</warn>
348</p>
349<pre caption="only if you get an error when running amixer">
350# <i>modprobe snd-mixer-oss</i>
351# <i>modprobe snd-pcm-oss</i>
352# <i>amixer</i>
353</pre>
354<p>
355If you got this far, now unmute Master and PCM channels. Some hardware
356even requires you to unmute the center channel or even the surround
357channel.
358</p>
359<p>
360<pre caption = "Unmuting channels">
361# <i>amixer set Master 100 unmute</i>
362# <i>amixer set PCM 100 unmute</i>
363<comment>Only if the above doesn't succeed on its own:</comment>
364# <i>amixer set Center 100 unmute</i>
365# <i>amixer set Surround 100 unmute</i>
366<comment>Test the sound:</comment>
367# <i>aplay $KDEDIR/share/sounds/pop.wav</i> <codenote>(pop.wav is part of KDE)</codenote>
368</pre>
369</p>
370We check to see if sound is working by using the aplay (alsa play) command. If you hear a pop, then sound is indeed working.
371Then, adjust the volume settings to your liking; the ncurses-based <c>alsamixer</c> is a great way to get them "just so".
372<p>
373You may want to emerge <c>alsa-xmms</c> as that will provide ALSA support for XMMS.
374</p>
375When you reboot your system, the <e>alsasound</e> init script will properly save and restore your volume settings.
376</body>
377</section> 967<section>
378</chapter> 968<title>Multiple sound cards</title>
379<chapter> 969<body>
380<title>Final Notes</title> 970
971<p>
972You can have more than one sound card in your system simultaneously, provided
973that you have built ALSA as modules in your kernel (or have installed
974<c>alsa-driver</c> instead). You just need to specify which should be started
975first in <path>/etc/modules.d/alsa</path>. Your cards are identified by their
976driver names inside this file. 0 is the first card, 1 is the second, and so on.
977Here's an example for a system with two sound cards.
978</p>
979
980<pre caption="Two sound cards in /etc/modules.d/alsa">
981options snd-emu10k1 index=0
982options snd-via82xx index=1
983</pre>
984
985<p>
986Or, if you have two cards that use the same driver, you specify them on the same
987line, using comma-separated numbers. Here's an example for a system with three
988sound cards, two of which are the same Intel High Definition Audio card.
989</p>
990
991<pre caption="Multiple sound cards in /etc/modules.d/alsa">
992options snd-ymfpci index=0
993options snd-hda-intel index=1,2
994</pre>
995
996</body>
381<section> 997</section>
382 <title>After kernel-upgrades..</title>
383<body>
384<p>When you ever rebuild your kernel, or upgrade to another kernel, you'll have to rebuild the ALSA modules.</p>
385<p>Although you might have installed <c>alsa-driver</c>, <c>alsa-libs</c> and <c>alsa-utils</c>, only the first will
386have to be installed again, since it will put the alsa modules in
387<path>/lib/modules/*/kernel/sound/pci/</path>.</p>
388<pre caption="needed after each kernel compile">
389# <i>emerge alsa-driver</i>
390</pre>
391</body>
392</section> 998<section>
999<title>Plugins</title>
1000<body>
1001
1002<p>
1003You may want to install some plugins for extra functionality.
1004<c>alsa-plugins</c> is a collection of useful plugins, which include: PulseAudio
1005output, a sample rate converter, jack (a low-latency audio server), and an
1006encoder that lets you output 6-channel audio through digital S/PDIF connections
1007(both optical and coaxial). You can choose which of its plugins you want
1008installed by adding their USE flags to <path>/etc/portage/package.use</path>.
1009</p>
1010
1011<pre caption="Installing alsa-plugins">
1012# <i>emerge -avt alsa-plugins</i>
1013</pre>
1014
1015</body>
393<section> 1016</section>
394 <title>/etc/modules.autoload</title>
395<body>
396<p>You won't have to edit this file for use with ALSA. After our <c>rc-update add alsasound boot</c>, our system will
397load the correct modules at startup.</p>
398<p>It's not necessary to add <c>snd-pcm-oss</c> or <c>snd-mixer-oss</c> in this file.
399Check the <uri link="http://www.djcj.org/LAU/guide/alsbook/faq1.html">this FAQ</uri> for more info.</p>
400</body>
401</section> 1017<section>
1018<title>A big thank you to...</title>
1019<body>
402 1020
1021<p>
1022Everyone who contributed to the earlier version of the Gentoo ALSA Guide:
1023Vincent Verleye, Grant Goodyear, Arcady Genkin, Jeremy Huddleston,
1024John P. Davis, Sven Vermeulen, Benny Chuang, Tiemo Kieft and Erwin.
1025</p>
1026
1027</body>
403<section> 1028</section>
404<title>Known bugs</title> 1029<section>
1030<title>References</title>
405<body> 1031<body>
406
407<note>
408This guide lags behind on the alsa-development. Chances are these bugs
409are already fixed when you read this.
410</note>
411 1032
412<ul> 1033<ul>
413<li> 1034 <li><uri link="http://www.alsa-project.org/">The ALSA Project</uri></li>
414If you have <b>lots of noise</b> when using <b>oss</b> emulation, add 1035 <li><uri link="http://linux-sound.org">Linux Sound/MIDI Software</uri></li>
415<e>options snd-pcm-oss dsp_map=1</e> to
416<path>/etc/modules.d/alsa</path>.
417</li>
418</ul> 1036</ul>
419 1037
420</body>
421</section>
422
423<section>
424 <title>More links..</title>
425<body>
426<p>
427You could check these for additional info:
428</p>
429<p>
430<ul>
431<li><uri link="http://www.gentoo.org/doc/en/desktop.xml">The Gentoo Linux Desktop Configuration Guide</uri></li>
432<li><uri link="http://www.alsa-project.org">ALSA Project Homepage</uri></li>
433<li><uri link="http://www.alsa-project.org/documentation.php3">ALSA Users Documentation</uri></li>
434<li><uri link="http://www.djcj.org">ALSA Howto's and FAQ's</uri></li>
435<li><uri link="http://tldp.org/HOWTO/Sound-HOWTO/index.html">Linux Sound HOWTO</uri></li>
436<li><uri link="http://linux-sound.org/">Sound and MIDI Software For Linux</uri></li>
437</ul>
438</p>
439</body> 1038</body>
440</section> 1039</section>
441</chapter> 1040</chapter>
442</guide> 1041</guide>

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